Optical identification element using separate or partially overlapped diffraction gratings

Abstract

An optical identification element 8 includes an optical substrate 10 having at least one diffraction grating 12 disposed therein. The grating 12 has a one or more of collocated pitches A which represent a unique identification N bit digital code that is detected when illuminated by incident light 24. The incident light 24 may be directed transversely onto the side or onto an end of the substrate 10 with a narrow band (single wavelength) or multiple wavelength source, in which case the code is represented by a spatial distribution of light or a wavelength spectrum, respectively. The element 8 can provide a large number of unique codes, e.g., greater than 67 million codes, and can withstand harsh environments. The element 8 can be used in any application that requires sorting, tagging, tracking or identification, and can be made on a micron scale “microbeads” if desired, or larger “macro-elements” for larger applications. The code may be digital binary or may be other numerical bases.

Description

CROSS REFERENCES TO RELATED APPLICATIONS [0001] This application is a continuation-in-part of, and relates and claims benefit to U.S. patent application Ser. No. 11 / 063,666 (CV-0065USCIP), filed 22 Feb. 2005, “Optical Identification Element Using Separate or Partially Overlapped Diffraction Gratings”, which itself claims benefit to U.S. provisional patent application Ser. No. 60 / 547,013 (CV-0065PR), entitled “Optical Identification Element Using Separate or Partially Overlapped Diffraction Gratings”, filed Feb. 19, 2004, which are both hereby incorporated by reference in their entirety. [0002] This application also relates to U.S. provisional patent application Ser. Nos. 60 / 546,445 (CV-0035PR), entitled “Optical Identification Element Having Non-waveguide Photosensitive Substrate with Bragg Grating Therein”; and 60 / 546,435 (CV-0053PR), entitled “Multi-well Plate with Alignment Grooves for Encoded Microparticles”, all filed Feb. 19, 2004 and hereby incorporated by reference in their ...

AI Technical Summary

Benefits of technology

[0009] Objects of the present invention include provision of an optical identification element or platform that allows for a large number of distinct codes, can be made very small, and / or can withstand harsh environments.

Problems solved by technology

Existing technologies, such as bar codes, electronic microchips / transponders, radio-frequency identification (RFID), and fluorescence and other optical techniques, are often inadequate.

For example, existing technologies may be too large for certain applications, may not provide enough different codes, or cannot withstand harsh temperature, chemical, nuclear and / or electromagnetic environments.

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